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WEED FLORA OF IOWA 



Fig. 206-A. Distribution of Tickseed. 



Extermination. — This weed is easily exterminated by cultiva- 

 tion. Do not permit seeds to mature. 



Sneezeweed (Helenium autumnale L.). 



Description. — A smooth, angular, branching perennial, 1-5 ft. 

 high; mostly toothed, lanceolate-ovate oblong; heads yellow, ap- 

 pearing in autumn ; involucre of the head or flower consists of 

 small reflexed scales ; ray and disk flowers yellow and fertile ; seeds 

 top-shaped and ribbed; pappus consisting of 5-8 thin, 1-nerved, 

 chaffy scales. 



Distribution. — Native to the northern states, particularly from 

 Missouri and Illinois to Wisconsin and Minnesota; in the Dakotas 

 as well as in the Rocky mountains, Utah and the northwest. 



Extermination. — This weed occurs only in low grounds. The 

 soil should be drained. Then sow to some useful leguminous crop 

 like alsike clover. The weed succumbs readily to cultivation. 



